Consisting of more than 13 million B&W and color photographs, the Corbis-Bettmann Archive photography collection spans almost the entire technological history of photography. When the collection was acquired by Bill Gates in 1995, the condition of the materials ranged from almost pristine, in the case of contemporary B&W negatives and color transparencies, to older, seriously faded color images and B&W negatives in which the acetate film base had deteriorated to the point that they were no longer recoverable. To halt further deterioration of this extraordinary collection – and ensure its survival for many thousands of years into the future – it was moved from New York City to an underground home where it would be protected from man-made and natural disasters and, literally, be frozen in eternity in secure sub-zero humidity-controlled storage.